Venting system for ovenable containers

ABSTRACT

The invention comprises an ovenable packaging structure having an integral one-way valve. The laminate structure comprises an outer layer having a cut line which defines a flap that is separable from the outer layer, wherein the outer layer is adhered to an inner layer having a cut line which is offset from the outer cut line and defines a portion that is separable from the inner layer along the inner cut line and defines an opening into the packaging structure. The adhesive between the layers comprises, in an embodiment, a channel of pressure sensitive adhesive which surrounds both the outer cut line and the inner cut line, wherein the channel of pressure sensitive adhesive defines the perimeter of at least one adhesive-free valve chamber within said channel. The valve chamber comprises at least a portion of the outer cut line and the inner cut line.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/446,873, filed Jun. 20, 2019, entitled “VENTING SYSTEM FOR OVENABLECONTAINERS”, which is incorporated herein in its entirety.

FIELD OF THE INVENTION

This invention relates generally to venting systems which are integralto a flexible laminate structure and which are configured to allow gasto vent from within a package during oven or microwave heatingprocesses.

BACKGROUND

Many frozen and/or fresh food products are packaged in containers whichare designed to be ovenable—i.e. the container and the food products canbe heated in an oven or microwave. For example, prepared, ready-to-eator frozen meals are packaged in a manner such that they can be removedfrom the refrigerator or freezer and immediately heated in an oven ormicrowave.

Typically, the package comprises a receptacle to hold the food, such asa tray. A lidding film may be attached to the tray. The film may protectthe food from the environment and may provide the food product with auseful shelf life. The tray may be further packaged within an outersleeve, such as a paperboard sleeve or a flexible plastic sleeve bearingproduct information. The outer sleeve may or may not be hermeticallysealed.

In typical use, a user removes any outer packaging, such as the outersleeve, punctures the lidding film or partially peels back the liddingfilm, and then places the package into an oven or microwave for heating.After heating, the lid is fully removed and the food is consumeddirectly from the tray or transferred from the tray to a plate or bowlfor consumption.

Packages that are warmed in the oven or microwave without some form ofventing (puncture, partial removal, etc.) will expand as steam developswithin the packaging and the seals, film, or tray may fail or burstunder pressure. If the user is required to manually create the vents,there is a chance that the manual piercing or puncture will not beaccomplished correctly (i.e. too much damage to the lidding film). Insuch case, an insufficient amount of steam may be generated within thepackage and the resulting food product may be dry and unsatisfactory.Likewise, the manual piercing or puncture may not be sufficient and toomuch steam may be generated internally, leading to partial or total sealfailures, tears, and/or bursting. As an alternative to piercing orpartially removing the lidding film, laser micro perforations may beused to relieve internal pressures without requiring the user tomanually adjust the packaging to relieve pressure, but creating microperforations in such packaging requires an additional step in themanufacturing process, adding expense and time to the process.

SUMMARY OF THE INVENTION

Through hard work and ingenuity, the inventors have developed anintegrated venting system for ovenable food containers. The inventivecontainers have an integral pathway for steam to escape from theinterior of the container, thereby avoiding a failure of the heat sealbonds, unwanted tears or venting, or bursting in the package's weakestarea. The venting pathway is created by a specific configuration ofadhesive, adhesive-free areas, and die cuts. In an embodiment of theinvention, at least one adhesive-free region is disposed along theinterface between two flexible laminate layers, along the location ofthe edge of a flap formed in the layers. There is at least one diecut inthe lower film and at least one offset diecut in the upper film, each atleast partially located in the adhesive-free region. The steam passesfrom the lower diecut, through the adhesive-free region, to the upperdiecut, and out of the packaging. In an embodiment, the lower and upperdie cuts are the same diecuts used to form the integral peelable flap.Thus, there are no additional steps or expense incurred in themanufacturing process. The consumer is not required to peel, remove,tear, pierce, or replace any film prior to heating. Thus, there is norisk of user error with regard to venting. After heating the foodproduct and allowing steam to escape, the top film layer is peeled backfor access to the food product. The peelable flap may be completelyremoved and discarded or replaced onto the container, to reseal thecontainer.

Embodiments of the invention described herein provide improved packagesfor storing products and associated methods for forming such packages,where the packages are designed to allow gas and steam generated withinthe package to escape to the external environment while at the same timeminimizing or preventing oxygen and/or moisture from entering thepackage.

In an embodiment, the invention is directed to an ovenable packagingstructure having an integral one-way valve comprising an outer flexiblestructure having an outer cut line which defines a flap that isseparable from the outer flexible structure along the outer cut line; aninner flexible structure having an inner cut line which defines an inneropening portion that is separable from the inner structure along theinner cut line, wherein the inner cut line is offset from the outer cutline, and wherein when the inner opening portion is separated from theinner structure, an opening into the ovenable packaging structure iscreated; an adhesive layer which adheres the outer flexible structure tothe inner flexible structure, wherein the adhesive layer comprises achannel of pressure sensitive adhesive which surrounds both the outercut line and the inner cut line, wherein the channel of pressuresensitive adhesive defines the perimeter of at least one adhesive-freevalve chamber within said channel, and wherein the valve chambercomprises at least a portion of the outer cut line and the inner cutline; and a region of permanent adhesive which adheres at least theinner opening portion of the inner flexible structure to the flap of theouter flexible structure

In another embodiment, the invention is directed to an ovenablepackaging structure having an integral one-way valve comprising an outerflexible structure having an outer cut line which defines a flap that isseparable from the outer flexible structure along the outer cut line; aninner flexible structure having an inner cut line which defines an inneropening portion that is separable from the inner structure along theinner cut line, wherein the inner cut line is offset from the outer cutline, and wherein when the inner opening portion is separated from theinner structure, an opening into the ovenable packaging structure iscreated; wherein a marginal region of the flap is defined between theinner and outer cut lines, the marginal region overlying an underlyingsurface of the inner structure, wherein a pressure sensitive adhesive isdisposed on one of the marginal region of the flap and the underlyingsurface of the inner structure, wherein the pressure sensitive adhesivedefines the perimeter of at least one adhesive-free valve chamber withinthe marginal region, and wherein the valve chamber comprises at least aportion of the outer cut line and the inner cut line.

In yet another embodiment, the invention is directed to a method ofmaking an integrally-vented ovenable packaging structure comprisingproviding a first film layer and a second film layer; applying at leasta pressure sensitive adhesive to at least one of the first film layer orthe second film layer, wherein the pressure sensitive adhesive isapplied in a track configuration, and wherein pressure sensitiveadhesive is not applied to at least one adhesive-free valve chamberdisposed within the track of pressure sensitive adhesive; laminating thefirst film layer to the second film layer; scoring a first cut linethrough the first film layer, wherein at least a portion of the firstcut line is disposed within the valve chamber and wherein the first cutline defines a flap that is separable from the first film layer alongthe first cut line; and scoring a second cut line through the secondfilm layer, wherein the second cut line is offset from the first cutline, wherein the second cut line defines an inner opening portion thatis separable from the second film layer along the second cut line, andwherein at least a portion of the second cut line is disposed within thevalve chamber.

In a still further embodiment, the invention is directed to an ovenablepackaging structure having an integral one-way valve comprising a firstfilm layer at least partially adhered to a second film layer with apressure sensitive adhesive, wherein the pressure sensitive adhesive isdisposed in a track configuration, and wherein at least oneadhesive-free valve chamber is disposed within the pressure sensitiveadhesive track; a first cut line disposed through the first film layer,wherein at least a portion of the first cut line is disposed within thevalve chamber and wherein the first cut line defines a flap that isseparable from the first film layer along the first cut line; and asecond cut line disposed through the second film layer, wherein thesecond cut line is offset from the first cut line, wherein the secondcut line defines an inner opening portion that is separable from thesecond film layer along the second cut line, and wherein at least aportion of the second cut line is disposed within the valve chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described the disclosure in general terms, reference willnow be made to the accompanying drawings, which are not necessarilydrawn to scale, and wherein:

FIGS. 1A-1B illustrate a top view of the layers of the laminate, in anembodiment, and FIG. 1C illustrates the laminate itself, in anembodiment of the invention;

FIG. 2 illustrates an embodiment of a container of the invention;

FIGS. 3A and 3B illustrate an embodiment of a container of the inventionin a closed (3A) and open (3B) configuration;

FIGS. 4A and 4B illustrate an exploded cross-sectional view of the valvechamber of the invention, in an embodiment; and

FIGS. 5A-5D illustrate various valve chamber configurations of theinvention, in an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings in which some but not allembodiments of the invention are shown. Indeed, the invention may beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will satisfy applicable legalrequirements. Like numbers refer to like elements throughout.

In an embodiment, the invention comprises a laminate which may beapplied to a container or package. In this embodiment, the container orpackage may comprise a flange, rim, or edge and the inventive laminatemay be adhered to that flange, rim, or edge. In another embodiment, theinvention comprises a multi-ply flexible package. The invention may ormay not comprise a rigid tray disposed within the flexible package. If arigid or semi-rigid tray is disposed within the package, the packagingmay be adhered to at least a portion of the tray. In an embodiment, thetray comprises a flange and the packaging is at least partially adheredto the flange of the tray. Regardless of the configuration, a foodproduct may be enclosed within the package and/or tray, and the packagemay be designed for heating of that food product while within thepackage.

In an embodiment, the laminate and/or package is configured to have abuilt-in opening and reclose feature—also referred to herein as a flap.The built-in opening and reclose feature is created, in an embodiment,by forming the laminate or packaging structure as a two-part structure,having an outer structure joined in face-to-face relation with an innerstructure. Each of the outer and inner structures can comprise one ormore layers of flexible packaging material such as polymer film, paper,metal foil, and/or the like. An outer line of weakness is formed in theouter structure to define an outer opening portion that can be liftedout of the plane of the outer structure. Similarly, an inner line ofweakness is formed in the inner structure to define an inner openingportion that can be lifted out of the plane of the inner structure. Theouter and inner opening portions are adhered to each other such that theouter and inner opening portions can be lifted out of the plane as aunit (i.e. a flap), thereby creating an opening through the packagingstructure, defined by the inner line of weakness, and into the package.

In an embodiment, the outer opening portion is larger in area than theinner opening portion and has a marginal region that extends beyond theperipheral edge of the inner opening portion. When the outer and inneropening portions are lifted out of the plane to create the opening, anunderlying portion of the inner structure in registration with themarginal region of the outer opening portion is exposed adjacent theopening. This may be referred to as the marginal region of the innerstructure. A pressure-sensitive adhesive is applied to either themarginal region of the outer opening portion or the underlying portionof the inner structure (the inner structure marginal region). Afterinitial lifting of the outer and inner opening portions, the openingthrough the structure can be reclosed by adhering the marginal region ofthe outer opening portion to the underlying portion (or marginal region)of the inner structure via the pressure-sensitive adhesive. A ventingsystem, as will be more fully described below, is disposed within themarginal region of the packaging.

Referring now to the drawings, FIGS. 1A and 1B illustrate a firststructure 10 and second structure 42 which may be utilized in anembodiment of the invention. The first structure 10 and/or the secondstructure 42 may be single ply or may comprise multiple layers offlexible packaging material. Various materials can be used for thelayer(s) of the first structure 10 and/or the second structure 42,including polymers such polyesters, polyolefins (including homopolymersand copolymers), polyamides, and others; paper; metal foil; and thelike. In a preferred embodiment of the invention, the first structure 10may include an outer layer that is substantially transparent, may bereverse-printed or outer surface printed, and/or may be printed withgraphics, logos, product information, etc. As an example, the firststructure 10 may comprise a layer of polyester such as polyethyleneterephthalate or the like.

In an embodiment, the first structure 10 is at least partially adheredor laminated to the second structure 42 via a layer of adhesive. In oneembodiment, the adhesive may comprise at least a pressure sensitiveadhesive (“PSA”) 20. The PSA 20 may be applied to either of the firststructure 10 or the second structure 42. The PSA layer 20 may be appliedin a predetermined pattern, in an embodiment. The predetermined patternmay be generally U-shaped, square, circular, ovular, or any other shapeknown in the art. The shape of the PSA layer 20 may mirror the shape ofthe container, generally, or the lid or flange, if applicable. The PSAlayer 20 may be a closed shape in some embodiments. In an embodiment,the PSA layer may be a continuous line in the shape of a square,circular, ovular, or any other shape known in the art. Alternatively,the PSA 20 may be disposed in a channel, track or ringconfiguration—that is, the PSA 20 may comprise a closed track of aparticular width (i.e. a circular track, square track, rectangulartrack, ovular track, or other closed shape). Similarly, the PSA 20 maybe disposed in an open channel, track or ring configuration—that is, thePSA 20 may comprise a track of a particular width but may be open on atleast one end (i.e. a U-shape, V-shape, or C-shape). Within the interiorof the track or channel (i.e. the area identified as numeral 86), PSA 20may or may not be present. An embodiment of this configuration is shownin FIGS. 1A-1C. It should be understood that any pattern of PSA 20 whichaccomplishes the purposes set forth herein may be utilized herein. Inother embodiments, the PSA layer 20 may be flood coated (i.e. 100% ornearly 100% coverage) onto either of the first structure 10 or thesecond structure 42, optionally avoiding adhesive-free areas (discussedbelow) or deadening the PSA 20 in such areas.

The PSA 20 may comprise a variety of compositions and can comprise anyPSA known in the art. Additives (e.g., particulates or the like) can beadded to the pressure-sensitive adhesive 20 to reduce the tenacity ofthe bond to the underlying structure, if desired, so that thepressure-sensitive adhesive 20 readily detaches from the oppositestructure on opening (particularly on the very first opening).

In another embodiment, the first structure 10 is at least partiallyadhered to the second structure 42 via a permanent adhesive 34. Anypermanent adhesive known in the art may be utilized. The permanentadhesive 34 may be applied to either of the first structure 10 or thesecond structure 42. The permanent adhesive 34 may be applied in apredetermined pattern or may be flood coated. If pattern applied, thepattern of permanent adhesive 34 may be generally U-shaped, square,circular, ovular, or any other shape known in the art. The shape of thepermanent adhesive 34 may mirror the shape of the container, generally,or the lid or flange, if applicable. The permanent adhesive 34 may be aclosed shape in some embodiments. In an embodiment, the permanentadhesive 34 may be a continuous line in the shape of a square, circular,ovular, or any other shape known in the art. Alternatively, thepermanent adhesive 34 may be disposed in a channel, track or ringconfiguration—that is, the permanent adhesive 34 may comprise a closedtrack of a particular width (i.e. a circular track, square track,rectangular track, ovular track, or other closed shape). It should beunderstood that any pattern of permanent adhesive 34 which accomplishesthe purposes set forth herein may be utilized herein. In otherembodiments, the permanent adhesive 34 may be flood coated (i.e. 100% ornearly 100% coverage) onto either of the first structure 10 or thesecond structure 42, optionally avoiding adhesive-free areas (discussedbelow) or deadening the permanent adhesive 34 in such areas.

In some embodiments, a combination of permanent adhesive 34 and PSA 20is utilized. In this embodiment, the permanent adhesive 34 may beapplied outside the perimeter of the PSA 20 and may mirror the shape ofthe PSA 20. In another embodiment, the permanent adhesive 34 may beapplied outside the perimeter of the PSA 20 and throughout the remainderof the packaging structure. In an embodiment, the permanent adhesive 34may be applied inside the perimeter of the PSA 20 and may mirror theshape of the PSA 20. In an embodiment, the PSA 20 may be disposed in atrack configuration and the permanent adhesive 34 may be disposedoutside and inside the perimeter of the PSA 20 track. In an embodiment,the permanent adhesive 34 does not cover the PSA 20. In an embodiment,the permanent adhesive 34 may be disposed throughout the interface ofthe first structure 10 and the second structure 42 but for any PSA 20areas and any adhesive-free areas (discussed below).

While use of both PSA 20 and permanent adhesive 34 are contemplatedherein, it should also be understood that the first structure 10 and thesecond structure 42 could utilize only PSA 20 between them. Likewise,the first structure 10 and the second structure 42 could utilize onlypermanent adhesive 34 between them. In the latter embodiment, thepackage may not be resealable, which is an embodiment encompassed by theinvention.

In an embodiment, there is at least one interrupted portion 22 whereinthe otherwise continuous pattern of adhesive (whether it is PSA 20,permanent adhesive 34, or a combination thereof) is interrupted or isdiscontinuous. In this embodiment, the first structure 10 and the secondstructure 42 may both be adhesive-free in the interrupted area 22. Thatis, between first structure 10 and second structure 42, there may be aninterrupted region 22 which contains no adhesive (or any appliedadhesive may be deadened), but is otherwise surrounded by adhesive. Inan embodiment, the interrupted portion 22 may appear as a patch, in thatit is an adhesive-free area surrounded by either PSA 20, permanentadhesive 34, or a combination of PSA 20 and permanent adhesive 34. In anembodiment, the disposition of the adhesive defines the perimeter of theinterrupted region 22 (and thereby, the valve chamber, discussed below).In an embodiment, the PSA 20 is disposed in a channel or trackconfiguration (shown in FIG. 1 ) and the at least one interrupted region22 is disposed within the interior of the track. That is, theinterrupted region 22 is surrounded on all sides by PSA 20 which isdisposed in a track configuration.

The first structure 10 may comprise a first, or outer, score line 52formed through its thickness. In an embodiment, score line 52 defines aflap or outer opening portion 86 (shown in FIG. 2 ) which is peeled backto create an opening through the laminate. The flap 86 may be peelableand replaceable or may be entirely removable from the packagingstructure. The flap 86 defined by score line 52 may be a closed shape(see FIG. 2 ), such as a square, rectangle, circle, oval or ellipse, inan embodiment. In this embodiment, score line 52 may be continuous. Inother embodiments, the flap 86 may be cut on multiple, but not all ofits sides. For example, the flap 86 may be cut on three sides but mayremain attached to the packaging structure on its fourth side, as shownin FIGS. 3A and 3B. In this embodiment, score line 52 is discontinuous.

Outer score line 52 and/or inner score line 62 may be referred to hereinas a cut line and/or line of weakness. It should be understood that theterms “line of weakness,” “cut line” and “score line,” as used herein,may refer either to a complete cutting through the thickness of one ormore layers 10, 42, a partial cutting through of the thickness of suchlayer(s) allowing the layer(s) to be severed along the score line,and/or a perforation wherein each of the perforations extends completelythrough the thickness of one or more layers 10, 42, allowing thelayer(s) to be severed along the score line.

In an embodiment wherein both PSA 20 and permanent adhesive 34 areutilized, and the first score line 52 may be in registration with (i.e.,coincides with) the outer perimeter of the PSA 20. In anotherembodiment, however, the first score line 52 is at least partiallyinside the outer perimeter of the PSA 20—that is the PSA 20 extends atleast partially outwardly beyond, or across, the first score line 52. Inan embodiment, score line 52 is continuous (meaning connectedend-to-end) and is contained within a track configuration of the PSA 20.That is, on both sides of score line 52, PSA 20 is disposed. In anembodiment, the first score line 52 extends substantially or entirelythrough the thickness of the first structure 10, but does not extend toany substantial extent into the second structure 42.

In an embodiment, the second structure 42 may also comprise a second, orinner, score line 62 formed through its thickness. In an embodiment,score line 62 defines an opening into the packaging. In an embodiment,the second score line 62 is spaced inwardly of the first score line 52so as to define an inner opening portion 88 of the second film structure42, which is of smaller area than the flap 86 formed in the first filmstructure 10. In any case, the second score line 62 is offset from thefirst score line 52.

In an embodiment wherein the PSA 20 has been pattern-applied, the secondscore line 62 may be in registration with (i.e., coincides with) theinner perimeter of the pattern of PSA 20. In another embodiment,however, the second score line 62 may be at least partially inside theouter perimeter of the pattern of PSA 20—that is, the PSA 20 may extendat least partially beyond, or across, the perimeter of the second scoreline 62. In an embodiment, score line 62 is continuous (i.e. connectedend-to-end) and is contained within a track configuration of the PSA 20.That is, on both sides of score line 62, PSA 20 is disposed. In anembodiment, the second score line 62 extends substantially through thethickness of the second structure 42, but preferably does not extend toany substantial extent into the first structure 10.

In a particular embodiment, the PSA 20 is disposed in a trackconfiguration, score line 62 is end-to-end continuous and is containedwithin the track configuration, and score line 52 is end-to-endcontinuous and is contained within the track configuration. In anotherembodiment, the PSA 20 is disposed in a track configuration, score line62 is contained within the track configuration, and score line 52 iscontained within the track portion. That is, on both sides of each ofthe score lines 52, 62, PSA 20 is disposed. In an embodiment, the PSA 20is disposed in a track configuration, score line 62 is disposed withinthe track configuration, score line 52 is disposed within the trackconfiguration, and an interrupted area 22 is disposed within the trackconfiguration, wherein the interrupted area 22 is surrounded by PSA 20.

In a different embodiment, the PSA 20 is disposed in a U-shapedconfiguration, score line 62 is not end-to-end continuous and isdisposed within the U-shaped configuration, and score line 52 is notend-to-end continuous and is disposed within the U-shaped configuration.That is, on both sides of each of the score lines 52, 62, PSA 20 isdisposed. In this embodiment, interrupted area 22 is disposed within theU-shaped PSA 20 configuration, wherein the interrupted area 22 issurrounded by PSA 20.

As further described below, the inner opening portion 88 is adhered tothe outer flap 86 (either by the permanent adhesive 34 or by thepressure-sensitive adhesive 20, applied between the two structures 10,42), such that both portions 86, 88 are lifted together and remainadhered when opening the package. That is, when the flap 86 is pulledaway from the packaging, the inner opening portion 88 separates from theremainder of the second structure 42 and lifts with the flap 86. In anembodiment, the inner opening portion 88 is a closed shape (regardlessof the shape of the flap) and separates entirely from the remainder ofthe inner structure 42 upon opening. In an embodiment, the inner openingportion 88 remains permanently affixed to the flap 86 throughout theopening and reclose processes. In an embodiment, inner opening portion88 defines the opening into the package upon opening.

In an embodiment, as described above, at least one interrupted area 22is disposed within the perimeter of the PSA 20 zone. The interruptedarea 22 is adhesive free. In an embodiment, a valve chamber 27 isdefined within or comprises the interrupted area 22 of the laminate. Thevalve chamber 27 includes at least a portion of first score line 52 andsecond score line 62. In an embodiment, these portions of first scoreline 52 and second score line 62 are the inlet and outlet valves of thevalve chamber 27. Thus, because first score line 52 and second scoreline 62 are formed as part of the construction of the inner openingportion 88 and the flap 86, no extra cutting or scoring steps are neededin the manufacturing process. The valves and the valve chamber 27 areintegral to the construction of the laminate 75.

In an embodiment, score line 62 is disposed inside or interior of (withreference to the perimeter of the container), or is offset from (e.g.,spaced apart from), score line 52. In an embodiment, a channel iscreated between the score lines 52 and 62. In an embodiment, gasses orsteam formed inside the package may escape from the package by travelingfrom cut line 62, through the channel, to cut line 52, and may then exitthe package. Because there is no adhesive in the valve chamber 27,gasses and steam may pass through the chamber once the pressure withinthe package exceeds the pressure outside the package.

The distance of the offset between the score lines 52 and 62 determinesthe length of the channel through which gasses or steam must flow toexit the packaging. For example, if score line 62 is disposed furtherfrom score line 52, the gas flow channel will be longer. If score line62 is disposed closer to score line 52, the gas flow channel will beshorter, which may allow gasses and steam to escape more easily. This,of course, must be balanced against providing a flap having a marginalregion which is functional—i.e. maintains its seal and is resealable, ifdesired. As noted above, in an embodiment, the valve chamber 27 isgenerally adhesive-free or any adhesive that has been applied in thearea of the valve chamber 27 has been deadened.

In an embodiment, the container comprises at least two interrupted areas22 and valve chambers 27. In this embodiment, the valve chambers 27 maybe located on opposite sides of the flap 86. In an embodiment, thecontainer comprises at least three interrupted areas 22 and valvechambers 27. In this embodiment, the valve chambers 27 may be locatedalong three different side edges of the flap 86.

A cross-section of an exemplary valve chamber 27, as taken along lineA-A of FIG. 1C, is shown in FIG. 4A in a closed position and in FIG. 4Bin an open position. With reference to FIGS. 4A and 4B, the valvechamber 27 includes a portion of the first and second cut lines 52, 62,such that the portion of first and second cut lines are contained withina perimeter of the valve chamber 27.

As noted, the valve chamber 27 may be an area of the flexible laminate75 that is devoid of adhesive 20, 34 adhering the first and second filmlayers 10, 42 to each other. In this way, the perimeter of the valvechamber 27 may be the intersection of an area including adhesive (PSA 20and/or permanent adhesive 34) and an area devoid of adhesive (or whereinthe adhesive has been deadened). Said another way, the adhesive 20, 34locations may define the perimeter of the valve chamber 27. In anembodiment, the valve chamber 27 is bounded on two sides by PSA 20 andon the other two sides by permanent adhesive 34. In another embodiment,the valve chamber 27 is bounded on all sides by PSA 20. In yet anotherembodiment, the valve chamber 27 is bounded on all sides by permanentadhesive 34.

In an embodiment, the valve chamber 27 is generally square, rectangular,ovular, circular, or elliptical. In another embodiment, the valvechamber 27 has an irregular or asymmetrical shape. The valve chamber 27shown in FIGS. 1A-1C, for example, has a symmetrical shape in onedimension (i.e. vertical or horizontal) but not in the other dimension.

FIGS. 5A-5D illustrate exploded views of a variety of shapes for valvechamber 27 which could be utilized. However, it should be understoodthat valve chamber 27 should not be limited to the shapes illustrated.Any shape known in the art may be utilized as the perimeter of the valvechamber 27.

Likewise, any size of the valve chamber 27 is encompassed in theinvention. In an embodiment, the valve chamber 27 may extend beyond eachcut line 52, 62 by a particular distance. In an embodiment, thatdistance may be between about ⅛ inch and ½ inch. In an embodiment, thenumber of valve chambers 27 disposed in the inventive system may be one,two, or more. Once a particular valve chamber vents the interior of thecontainer, the other valve chambers may not function due to the pressurerelief. Thus, having multiple valve chambers 27 may be advantageous insome embodiments.

In an embodiment described herein, the portions of the valve 27 whichintersect or cross cut lines 52, 62 are referred to as the “sides” ofthe valve, regardless of the shape of the valve itself. For example, thevalve 27 may be circular or ovular, but each portion of the perimeter ofvalve chamber 27 which crosses the cut line 52 and 62 may be referred toas a side. In this embodiment, the valve chamber 27 could have convexand/or concave sides on one or both sides of the valve chamber 27. In aparticular embodiment, valve chamber 27 could have one side which isconvex and the other side which is concave. In an embodiment, each sideof the valve has a curvature and each side is curved in the same manner,such that steam and/or gasses are directed from the inner cut line tothe outer cut line. In an embodiment, the sides of the valve which crossthe cut lines 52, 62 may be angled, but straight (not curved). In anembodiment, the sides of the valve may be angled in the same directionor in opposite directions. The sides of the valve which intersect orcross the cut lines 52, 62 may be parallel, in an embodiment. In anembodiment, the radius of curvature of the perimeter of the valvechamber 27 is the same or similar at the intersection of that perimeterwith cut line 52 and cut line 62.

In an embodiment, the shape of the valve chamber 27 may direct the flowof gasses from the interior cut line to the exterior cut line of thevalve. For example, in an embodiment shown in FIG. 5C, each side of thevalve chamber 27 curves inwardly, creating a more narrow channel frominterior cut line 62 toward exterior line 52, thereby directed gassesand steam to flow toward exterior cut line 52.

In an embodiment, the valve chamber 27 may comprise a viscous medium,such as oil 29. The oil 29 may be pattern-applied to at least one of thefirst 10 or second 42 film layers and may be disposed between the first10 and second 42 film layers so as to occupy at least a portion of thevalve chamber 27. The oil 29 may, for example, be silicone oil in somecases. The presence of the oil 29 may encourage the opposing surfaces ofthe first and second film layers 10, 42 (e.g., the surface of each filmlayer that is adjacent to or most proximate the other film layer) tomaintain contact with each other (with the oil disposed therebetween) byvirtue of the viscosity and/or surface tension of the oil, such that theintegrated valve is biased towards the closed position shown in FIG. 4Awhen the pressure inside the package is below a certain thresholdpressure. For example, in some embodiments, the volume of oil 29disposed between the first and second film layers 10, 42 is selectedsuch that the valve opens when the pressure inside the package justexceeds the atmospheric pressure outside the package. An example of adesirable range of pressures inside the package for moving the firstlayer 10 towards the open position shown in FIG. 4B is approximately 0.1psi to approximately 0.8 psi.

In some embodiments, an opposing surface of at least one of the first orsecond film layers 10, 42 may further include a surface treatmentconfigured to decrease an amount of surface energy between the first andsecond film layers in the valve area. The surface energy may becharacterized as the amount of energy required to adhere the opposingsurfaces of the first and second film layers 10, 42 to each other. Thus,while the addition of the oil 29 in the valve chamber 27 between theopposing surfaces of the first and second film layers 10, 42 serves toincrease the surface energy of the interface between the opposing filmsurfaces, the resulting surface energy may be too great to allow thevalve to open at the desired pressure level of the package interior. Theinclusion of the surface treatment for at least one of the opposingsurfaces of the first and second film layers 10, 42, however, maycounteract the increased adhesion force imparted by the oil 29, therebyreducing the surface energy to a level that allows the valve to be movedfrom the closed configuration to the open configuration when a desiredlevel of pressure is achieved within the package.

In some embodiments, for example, the surface treatment may comprise atleast one of a printed ink, a coating, or a texture that is applied toone or both of the opposing surfaces of the first and second film layers10, 42. The surface treatment (e.g., the printed ink, coating, ortexture) may serve to create bumps or ridges that extend from thesurface of the respective film layer 10, 42 that is treated toward theopposing surface of the other film layer.

Accordingly, the surface energy of the interface between the first andsecond film layers 10, 42 may be decreased due to the reduced contactarea between the two film layers. For example, instead of substantiallythe entire opposing surface of the first film layer 10 in the valve areacontacting substantially the entire opposing surface of the second filmlayer 42 in the valve area, in which case the surface energy would be ata maximum, the ridges created by the surface treatment in someembodiments may reduce the contact area to the sum of the areas overwhich each of the ridges contacts the corresponding locations of theopposing surface of the respective film layer. The inventors have foundthat the smaller the contact area, the less energy is required toseparate the first and second film layers 10, 42, and the less internalpackage pressure is needed to move the valve from the closedconfiguration to the open configuration. Accordingly, the type ofsurface treatment, the number of ridges created, and/or the amount ofinherent separation between the first and second film layers 10, 42caused by the extension of the ridges may be selected to achieve adesired surface energy that results in the opening of the valve at thedesired package pressure. In addition, the pattern of the ridges may beselected to further tune the opening and closure of the valve, dependingon the requirements of the package. In some cases, the thickness of thesurface treatment (e.g., thickness of the coating used), the roughnessimparted by the surface treatment (e.g., based on the chemical makeup ofthe surface treatment), and the location of the surface treatment mayalso affect the resulting surface energy.

In an embodiment, the laminate, label, and/or package includes anadhesive-free region to form a thumb tab or grasping portion 23. In thisembodiment, adhesive is not disposed (or is deadened) between the firststructure 10 and the second structure 42 in the location of the tab 23.Thus, the thumb tab 23 may comprise a portion of the first structure 10which is graspable because it is unadhered to the second structure 42.The thumb tab 23 may be defined by the score line 52, such that it iscontinuous with the flap 86.

The first score line 52 may, in an embodiment, include one or moretamper-evidence features 58. The tamper evidence features 58 maycomprise one or more areas in which the first structure 10 is not cut orscored along score line 52, and whose cut or uncut condition may bereadily apparent from a visual inspection of the first structure 10.Said another way, the score line 52 may have portions wherein the filmis not cut, between two portions of score line 52 which are cut. Thescore line 52 may be discontinuous in these areas. That is, the film onone side of the score line 52 may be continuous with the film on theother side of score line 52 in these areas. These areas may, in anembodiment, be referred to as the tamper-evidence features.

In an embodiment of use, the first structure 10 must be torn, throughthe tamper-evidence features 58, to connect the portions of the firstscore line 52 on opposite sides of each tamper-evidence feature 58. Inan embodiment, to help ensure that the two portions of the score linewill be connected even if the tear line tends to wander in a direction,the score line 52 at the “downstream” side of each tamper-evidencefeature 58 can terminate in a j-hook or U- or V-shaped portion thatextends generally transverse to the direction along which the score line52 extends. The “downstream” side refers to the side of thetamper-evidence feature that is located farthest along the downstreamdirection in which the flap 86 is peeled back when opening the package.In an embodiment, the first structure 10 is cut through its thicknessalong the transverse portion, similar to the rest of the score line 52.Accordingly, even if the tear line wanders to one side or the other, itwill connect with the transverse portion and thereby allow the scoreline 52 to continue to sever or separate as the flap 86 is peeledfarther back.

In an embodiment, the tamper-evidence features 58 are located withrespect to the outer score line 52 such that in order to lift the flap86 far enough to just begin lifting the inner opening portion 88 andthereby begin to create an opening into the package, the tamper evidencefeatures 58 must be torn through. In this regard, the tamper evidencefeature(s) 58 are not further along the downstream direction, or atleast are not substantially further along the downstream direction, thanis the most-upstream portion of the inner score line 62. In a particularembodiment, the tamper evidence feature 58 is located within theperimeter of or near the tab 23. While certain tamper-evidence features58 are discussed herein, it should be understood that any tamperevidence features known in the art are encompassed within the scope ofthe invention.

In an embodiment, the valve chamber(s) 27 are not located near the tab23 and/or the tamper evidence features 58, if any are present. In anembodiment, the valve chamber(s) 27 are located on a side of thepackaging that is opposite the tab 23 and/or the tamper evidencefeatures 58. In an embodiment, at least one of the valve chamber(s) 27are located along a corner of the flap 86 that is opposite the tab 23and/or the tamper evidence features 58. In an embodiment, at least oneof the valve chamber(s) 27 are located along a side of the flap 86 thatis not a side which comprises the tab 23 and/or the tamper evidencefeatures 58. In an embodiment, at least one of the valve chamber(s) 27are located on a side of the packaging that is opposite the tab 23and/or the tamper evidence features 58. In an embodiment, at least oneof the valve chamber(s) 27 are located at least half of the distance ofthe flap 86 away from the tab 23 and/or the tamper evidence features 58.Separating the valve 27 from the tab 23 and/or the tamper evidencefeatures 58 may help prevent issues with separation of the tab 23 and/orinterference with the tamper evidence features 58 when the steamreleases through the valve 27.

In one embodiment, the laminate 75 described herein (FIG. 1C) is alidding film which is affixed to the rim, edge, or flange 116 of a rigidor semi-rigid container to form a container assembly 110 (FIG. 2 ). Theflexible laminate 75 may comprise a lidding stock, for example, forforming flexible lids that can be secured (e.g., by heat-sealing or thelike) to a flange of a tray or other container that contains thecontents. In this embodiment, the laminate 75 may comprise a layer ofadhesive on the underside of the second film layer 42, such that layer42 can be adhered to the container.

In this embodiment, the lid includes a built-in opening and reclosefeature. For instance, FIG. 2 shows a package assembly 110 comprising acontainer body 112 having a side wall 114 and a flange 116 extendingoutwardly from the upper edge of the side wall. The container body 112can comprise various materials (e.g., polymer, paper, foil, etc.) andcan be formed by various methods (e.g., thermoforming, molding, etc.).The open top of the container body may be closed by a lidding laminate118 formed of a flexible laminate 75 in accordance with the invention.The lidding laminate 118 is sealed to the flange 116, in an embodiment,by any suitable technique, such that the lidding laminate 118 is firmlyattached to the flange. The lidding laminate 118 includes anopening/reclose feature formed by a first score line 52, second scoreline 62 and pressure-sensitive adhesive 20. The package 110 alsoincludes a thumb tab 23. As can be seen in FIG. 2 , the interrupted area22 is disposed entirely within the PSA 20 area, in an embodiment.

In another embodiment, the laminate 75 is used to form a flexiblepackage 70 which envelopes the contents (FIGS. 3A and 3B). Withreference to FIG. 3A, the package 70 is shown in a closed condition, forexample as initially filled and sealed in a packaging plant. FIG. 3Billustrates the package 70 in an open condition. It should be understoodthat while FIGS. 3A and 3B illustrate the package 70 as having anon-removable flap 86, the flap 86 may be completely removable in anembodiment. Thus, the cut lines 52, 62, may each define a closed shapein order to create such flap 86.

The package includes an outer wrapper 74 that envelopes the packagecontents and is sealed to enclose the contents. The outer wrapper 74 mayor may not container a rigid or semi-rigid tray which contains thecontents. In an embodiment, the outer wrapper 74 comprises a packaginglaminate 75 made by a method in accordance with the invention, such asthe laminate 75 previously described. The outer wrapper 74 ismanipulated into a tubular shape and the longitudinal edges of thewrapper 74 are sealed together by a suitable sealant material to form alongitudinal seal, typically adjacent the bottom surface of the package.The opposing portions of the wrapper 74 are sealed together alongtransverse seal lines 76, 78 adjacent the opposite ends of the tubularwrapper. The ends of the wrapper 74 can be gusseted if desired, as knownin the art.

In the illustrated package, the portion of the outer wrapper 74 havingthe score lines 52, 62 is provided on the top surface of the package.However, it should be understood that any surface of the package maycomprise the score lines 52, 62 and the flap 86. The area of the wrapper74 bounded by the score lines can constitute any fraction of the totaltop surface of the package. In an embodiment, the score lines 52, 62,have a small width, on the order of a few thousandths of an inch.

In either embodiment, there is an inner marginal region 90 on the inneropening portion 88 and an outer marginal region 91 on the flap 86. Thesemarginal regions are disposed atop one another. The outer marginalregion 91 extends from the edge of the flap 86 to at least the edge ofthe inner opening portion 88, and may extend beyond the inner openingportion 88. The inner marginal region 90 extends from the edge of theinner opening portion 88 to at least the edge of the flap 86, and mayextend beyond the flap 86.

PSA 20 is generally disposed between the first structure 10 and thesecond structure 42, on either or both of inner marginal region 90 andouter marginal region 91. In an embodiment, the PSA 20 is disposed onthe outer structure 10. In this embodiment, the outer structure 10preferably has a greater affinity for bonding with the PSA 20 than doesthe surface of the inner structure 42, and, upon opening the package,the PSA 20 is detached from the surface of inner structure 42 (in anembodiment) and remains attached to the outer marginal region 90 asshown in FIGS. 2 and 3B. Once opened, the package may be reclosable, inan embodiment, due to the PSA 20 in one or both of the marginal regions90, 91. The flap 86 may be reattached to the remainder of the laminate,using the PSA 20, to restore the package to a closed condition. Asnoted, although it is contemplated to apply the PSA 20 to the outerstructure 10 and to remain on the outer structure 10 upon opening, it isalso within the scope of the invention to apply the PSA 20 to the innerstructure 42 and to remain on the inner structure 42 upon opening.

Other than in adhesive-free or deadened areas, the first structure 10and second structure 42 may be joined by PSA 20 or a permanent adhesive34, between the structures, in all other areas.

The laminates made in accordance with the invention can be used forforming other types of packages as well. For instance, the laminate 75could be utilized in a stand-up pouch, flat-bottom bag, fin/lap sealbag, easy peel film, pillow pouch, or any other package known in theart.

In an embodiment, one or more of the film layers of the invention maycomprise a barrier layer or a sealant layer. The barrier layer maycomprise any of various barrier materials including barrier polymerfilms such as: ethylene vinyl alcohol copolymer (EVOH), polyamide, andthe like; metallized polyolefin films such as polyethylene,polypropylene, oriented polypropylene, and the like; AlOx-coated polymerfilms; SiOx-coated polymer films; metal foil; and others. The sealantlayer may constitute the innermost surface of the laminate 75, and cancomprise various sealant materials such as heat seals or cold seals.Heat seals generally are preferred because they provide stronger sealsthan cold seals typically are capable of achieving. Any suitable heatseal materials can be employed, such as polyethylene, polypropylene,ionomer resins such as SURLYN®, or others.

In an embodiment, the laminate 75 includes a metallization layer or ametal foil layer between the first structure 10 and the second structure42, for example by providing a metallization layer on the surface of thelayer that faces the first structure 10.

A method for making the packaging system of the invention is alsoprovided, in an embodiment. The first structure 10 is advanced from asupply roll to an optional print station for printing graphics and/orindicia on the first structure by applying inks to a surface of thefirst structure 10. Optionally, prior to printing the first structure inthe print station, the surface of the first structure that issubsequently laminated to the other structure may be treated by a coronadischarge or flame treatment apparatus to render the surface morereceptive to the inks and/or to render the surface more readily bondableto the pressure-sensitive adhesive that is subsequently applied to thesurface as described below.

The first structure 10 may then be advanced to a first adhesiveapplication station at which a PSA 20 is applied to the first structurein a predetermined pattern as described herein (or is flood-coated anddeadened). The adhesive application station may comprise a gravure rollor any other application equipment known in the art. After applicationof the pressure-sensitive adhesive 20, the first structure 10 isadvanced to a dryer such as an oven or the like, to dry thepressure-sensitive adhesive 20. In the case of the pressure-sensitiveadhesive 20 being pattern-applied, the first structure 10 may then beadvanced to a second adhesive application station at which a permanentlaminating adhesive 34 is applied to the first structure 10 in such amanner that a sufficiently large proportion of the surface is covered bythe permanent adhesive 34 to permit the first structure 10 to beadhesively attached to a second structure 42 at a downstream laminatingstation. Alternatively, the permanent adhesive 34 may be applied to thesecond structure 42 which may be adhesively attached to the firststructure 10 downstream. In an embodiment, permanent adhesive 34 isapplied in such a manner as to avoid the PSA 20 and adhesive-freeregions 22, 23. Alternatively, the permanent adhesive 34 may be deadenedin areas which will become the PSA region and the adhesive-free regions22, 23. A suitable adhesive application device can be a gravure roll,for example. After the application of the permanent adhesive 34, thefirst structure 10 is advanced to a dryer such as an oven or the like.

The first structure 10 is then advanced to a laminating stationcomprising a pair of rolls forming a nip therebetween. The firststructure 10 is passed through the nip along with a second structure 42that is advanced from its own supply roll and the first and secondstructures 10, 42 are laminated to each other. The second structure 42may be coextensive with the first structure 10—i.e., the width of thesecond structure 42 may be substantially equal to the width of the firststructure 10 and the longitudinal edges of the second structure 42substantially coincide with the longitudinal edges of the firststructure 10. The resulting laminate 75 may then be advanced to areel-up where it is wound into a roll for subsequent processing in thesecond phase of the manufacturing process as described below.Alternatively, it is possible for the reel-up operation to be omitted,such that the laminate 75 is directly advanced to the next phase.

The laminate 75 is advanced to a first scoring station at which a first,or outer, score line 52 is formed through the thickness of the firststructure 10. Next, the laminate 75 is advanced to a second scoringstation 60 at which a second, or inner, score line 62 is formed throughthe thickness of the second structure 42.

The scoring station can comprise a laser, die cutting machine, or anyother manner of cutting or scoring known in the art. For instance, akiss cut could be utilized. Additionally, it is within the scope of theinvention to laser-score one side of the laminate 75 and to kiss cut orotherwise mechanically score the other side. This can be advantageous,for example, when one of the structures making up the laminate 75 isreadily scored by a laser but the other structure is not. For instance,when the first structure 10 is a polyester such as PET, it can readilybe scored with a laser, but if a polyethylene heat seal layer isemployed on the opposite side, laser scoring may not be the best choicebecause polyethylene does not score well with a laser. In this case,kiss cutting or other mechanical scoring can be used to score the innerstructure 42.

After the scoring operations, the laminate 75 can be sent to a reel-upand wound into a roll for subsequent processing. The laminate 75 canalso be slit into a plurality of partial widths and wound into multiplerolls. In this latter instance, each partial width would have therecurring patterns of pressure-sensitive and permanent adhesives appliedwith suitably configured adhesive applicators to the full-widthmaterial, and would have the recurring score lines formed by suitablyconfigured scoring devices acting on either the full-width laminate 75prior to slitting or acting on each partial-width portion afterslitting.

Many other modifications and other embodiments of the inventions setforth herein will come to mind to one skilled in the art to which theseinventions pertain having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

The invention claimed is:
 1. A valve for use in ovenable packagingcomprising an outer flexible structure and an inner flexible structurejoined to the outer flexible structure by an adhesive layer, the valvecomprising: a first opening defined in the inner flexible structure; asecond opening defined in the outer flexible structure, wherein thesecond opening is spaced apart for the first opening; a channel definedbetween the first opening and the second opening; and a vicious mediumdisposed within the channel, wherein the vicious medium is configured tocreate a partial seal between the first opening and the second opening.2. The valve of claim 1, wherein the partial seal is ruptured due to apressure difference between the first opening and the second opening,wherein an inner pressure on a first opening side is greater than anouter pressure on a second opening side.
 3. The valve of claim 1,wherein the vicious material is oil.
 4. The valve of claim 1, whereinthe channel is void of an adhesive material.
 5. The valve of claim 1,wherein the channel comprises a layer of deadened adhesive.
 6. The valveof claim 1, wherein the channel is bound by a perimeter, wherein theperimeter is defined by the adhesive layer.
 7. The valve of claim 6,wherein the adhesive layer comprises a patterned permanent adhesive, anda patterned pressure sensitive adhesive.
 8. An ovenable laminatecomprising: an outer flexible structure having at least one overcut; aninner flexible structure having at least one undercut, wherein each ofthe at least one overcuts is paired with one of the at least oneundercuts; an adhesive layer which adheres the outer flexible structureto the inner flexible structure, wherein the adhesive layer comprises atleast one adhesive free area disposed within a channel between the atleast one overcut and at least one undercut, such that the channelprovides for fluid communication between the at least one overcut andthe at least one undercut.
 9. The ovenable laminate of claim 8, furthercomprising: a vicious medium disposed within the at least one adhesivefree zone.
 10. The ovenable laminate of claim 9, wherein the viciousmedium is configured to increase a surface energy between the outerflexible structure, and the inner flexible structure within the adhesivefree area, wherein the vicious medium is configured to prevent fluidcommunication through the channel.
 11. The ovenable laminate of claim10, wherein fluid communication through the channel is induced through apressure differential between an inner side associated with the innerflexible structure, and an outer side associated with the outer flexiblestructure, wherein the inner side defines a larger pressure than theouter side.
 12. The ovenable laminate of claim 9, wherein the viciousmedium is oil.
 13. A packaging structure comprising: the ovenablelaminate of claim 8 adhered to a container body.
 14. A packagingstructure comprising: the ovenable laminate of claim 8 defining alongitudinal seal, a first transverse seal line, and a second transverseseal line.
 15. An ovenable packaging structure comprising: an outerflexible structure having an outer cut line which defines a flap that isseparable from the outer flexible structure along the outer cut line; aninner flexible structure having an inner cut line which defined an innerportion that is separable from the inner structure along the inner cutline, wherein the inner cut line is off set from the outer cut line, andwhere in when the inner opening portion is separated from the innerstructure, an opening into the ovenable packaging structure is created;an adhesive layer disposed at least partially between the outer flexiblestructure and the inner flexible structure; and at least one valvedisposed between the outer flexible structure and the inner flexiblestructure, the valve comprising: an outer opening within the outerflexible laminate; an inner opening within the inner flexible laminate;a channel extending between the outer opening and the inner opening,wherein the channel is configured to provide fluid communication betweenthe inner opening and the outer opening.
 16. The ovenable package ofclaim 15, wherein the adhesive layer comprises: a region of permanentadhesive at least partially disposed between the flap and the inneropening portion; a region of pressure sensitive adhesive at leastpartially disposed between the inner cut line and the outer cut line;and a region of deadened adhesive at least partially disposed within theat least one valve.
 17. The ovenable package of claim 15, wherein theinner opening is along a portion of the inner cut line.
 18. The ovenablepackage of claim 15, wherein the outer opening is along a portion of theouter cut line.
 19. The ovenable package of claim 15 further comprisinga vicious medium disposed within the channel.
 20. The ovenable packageof claim 19, wherein the vicious medium is oil.